1. Field of the Invention
The invention relates to a mounting device for sensors, especially contactlessly-operating, cylindrical or cuboidal proximity switches, with a cylindrical or cuboidal recess to hold the proximity switch.
2. Description of Related Art
Proximity switches, because of their contactless mode of operation, have continuous almost ideal prerequisites for industrial use. They work without wear, enable high operating frequencies and operating accuracy and are invulnerable to vibrations, dust and moisture. For this reason proximity switches are being used in the millions and have proven their reliability in all areas for decades. Proximity switches are often used as limit switches for control of machinery. Depending on the application, inductive, capacitive, optical or optoelectronic proximity switches can be used as proximity switches.
Some of the proximity switches available in practice have a cylindrical structural shape, the housing of the proximity switch having an outside thread. This proximity switch is mounted by screwing the proximity switch into a corresponding threaded hole. When the proximity switch is adjusted, i.e., it has reached its intended position, it is fixed by means of at least one nut in the threaded hole. If the proximity switch must be replaced due to a defect, the newly inserted proximity switch must be readjusted in a complex manner, for which specialists are necessary, which in turn leads to significant downtime of the machine controlled by such a proximity switch.
To solve this problem, the use is known of a stop sleeve into which a proximity switch of conventional design is inserted. Readjustment is no longer necessary when the proximity switch is changed due to the fixed stop made on the stop sleeve. One such mounting device is known, for example, from German Utility Model DE 88 05 837. In this mounting device, the proximity switch is inserted into a receiving sleeve which is provided with an outside thread and is attached by means of a union nut.
German Patent DE 196 41 137 discloses a stop sleeve into which the proximity switch is inserted, the stop sleeve having a slotted end area into which an annular fixing element insert, having crosspieces that extend in the axial direction, can be inserted. By moving this fixing element into the slotted area of the stop sleeve the crosspieces are pressed to the inside, and the proximity switch is secured.
In addition, clamp-like holders for mounting of cylindrical proximity switches are known. These clamp-like holders have two separate clips which are drawn together by means of screws, after inserting the proximity switch, which thus fixes the proximity switch.
The known approaches for proximity switches which require the use of a stop sleeve have the principal disadvantage that they are suitable only for fixing cylindrical proximity switches. In addition, production of stop sleeves, having an outside thread and preferably having only a very small wall thickness while nevertheless being of high strength, is relatively complex and thus expensive.
It is common to all approaches that the final fixing of the proximity switch takes place by means of screws or union nuts so that the mounting device has several parts which can be lost, and requires the use of tools for fixing the proximity switch in position so that the replacement of a proximity switch is time-consuming. In addition, secure fixing of the proximity switch in no small degree depends on the screws or the union nuts being carefully tightened by the installer.
German Patent DE 199 00 876 discloses a mounting device for proximity switches which has a base body which in its top has a pivotally mounted fixing body with a clamp element.
Fixing of a proximity switch that has been inserted into the recess of the base body takes place by swiveling the fixing body which secures the proximity switch by way of the clamp element. With this mounting device, the fixing of the proximity switch without a tool is possible, however, the mounting device is relatively complex to produce due to the required swiveling support of the fixing body.